Snow blower attachment for lawnmowers and method of clearing snow

Abstract

An apparatus for clearing snow and other particulate material comprises one or a pair of arms mounted for rotation within the housing of a conventional rotary lawnmower or equivalent, as a substitute for the conventional grass-cutting blade. This enables the lawnmower to be used for clearing snow during the winter, when it cannot be used for cutting grass. The rotatable arm comprises an elongated blade member having upper and lower vanes extending upwardly and downwardly respectively from the blade member. The lower vanes act as knives to cut the snow or material to facilitate removal. The lower vanes are inclined obliquely to the blade axis so as to direct material that is below the blade member inwardly towards the axis of rotation. The upper vanes are inclined obliquely to a blade axis extending radially outwardly from the axis of rotation to direct material above the blade outwardly through a discharge opening of the housing. Inclination of the lower vanes with respect to the blade axis is in an opposite direction to the corresponding inclination of the adjacent upper vanes.

I claim: 
     
       1. A rotatable arm for clearing snow and other particulate or fragmented material, the arm comprising: (a) an elongated blade member having a mounting means located centrally between first and second outer end portions of the blade member, the mounting means being coincident with an axis of rotation of the blade member;   (b) first and second upper vane means extending upwardly from the first and second outer end portions of the blade member respectively, each upper vane means being inclined obliquely at an upper vane angle to a blade axis extending radially outwardly from the axis of rotation of the blade member; and   (c) first and second lower vane means extending downwardly from the first and second outer end portions of the blade member respectively, each lower vane means being inclined obliquely at a lower vane angle to the blade axis, inclination of the lower vane means with respect to the blade axis being in an opposite direction to corresponding inclination of the adjacent upper vane means, so that at a particular end portion of the blade member, the upper vane means is inclined at a net angle to the lower vane means when viewed along the axis of rotation.   
     
     
       2. A rotatable arm as claimed in claim 1 in which: (a) each lower vane means comprises at least one vane member inclined at an angle to the direction of rotation of the arm so as to direct the material that is below the blade member inwardly toward the axis of rotation of the blade member.   
     
     
       3. A rotatable arm as claimed in claim 2 in which: (a) each upper vane means is a vane member inclined at an angle to the direction of rotation of the arm so as to direct material that is above the blade member outwardly away from the axis of rotation of the blade member.   
     
     
       4. A rotatable arm as claimed in claim 1 in which: (a) the lower vane angle is between about 110 and 115 degrees, as measured on an inwardly disposed leading side of the blade axis defined with respect to direction of rotation of the blade member,   (b) the first and second lower vane means are disposed parallel to each other when viewed along the axis of rotation of the blade member.   
     
     
       5. A rotatable arm as claimed in claim 1 in which: (a) the upper vane angle is between about 55 degrees and 70 degrees, as measured on an inwardly disposed leading side of the blade axis defined with respect to direction of rotation of the blade member;   (b) the first and second upper vane means are disposed parallel to each other when viewed along the axis of rotation of the blade member.   
     
     
       6. A rotatable arm as claimed in claim 1 in which: (a) at least some of the vane means have faces disposed generally parallel to the axis of rotation of the blade member.   
     
     
       7. A rotatable arm as claimed in claim 1 in which: (a) at least some of the vane means have faces disposed generally perpendicularly to a plane containing a main face of the blade member.   
     
     
       8. A rotatable arm as claimed in claim 1 in which: (a) at least two of the vane means are generally U-shaped channel members secured to respective end portions of the blade member to provide a pair of parallel faces adjacent each said end portion.   
     
     
       9. A rotatable arm as claimed in claim 8 in which: (a) each lower vane means comprises one of said channel members secured to the respective outer end portion of the blade member to provide multiple cutting edges.   
     
     
       10. A rotatable arm as claimed in claim 1 in which: (a) the blade member is an essentially straight, generally flat strip having a longitudinal blade axis extending from the axis of rotation,   (b) the lower vane means provide a plurality of generally vertically disposed cutting edges,   (c) the upper vane means provide a plurality of fan blades to discharge air outwardly from the axis of rotation.   
     
     
       11. A rotatable arm as claimed in claim 10 in which: (a) the outer end portions of the blade member are bent generally perpendicularly to the flat strip along respective bend axes disposed obliquely to the blade axis to form one set of first and second vane means.   
     
     
       12. An apparatus for clearing snow and other particulate material, the apparatus comprising: (a) a housing having a top portion and a peripheral rim portion extending downwardly from the top portion to define a downwardly facing recess, the rim portion having a discharge opening;   (b) ground bearing means mounting the housing for movement along the ground;   (c) a motor mounted on the housing and having an output shaft rotatable within the recess;   (d) an elongated blade member having mounting means located centrally between first and second outer end portions of the blade member, the mounting means mounting the blade member on the output shaft for rotation about an axis of rotation of the blade member and the motor within the recess;   (e) first and second upper vane means extending upwardly from the first and second outer end portions of the blade member respectively, each upper vane means being inclined obliquely at an upper vane angle to a blade axis extending radially outwardly from the axis of rotation of the blade member;   (f) first and second lower vane means extending downwardly from the first and second outer end portions of the blade member respectively, each lower vane means being inclined obliquely at a lower vane angle to the blade axis, inclination of the lower vane means with respect to the blade axis being in an opposite direction to corresponding inclination of the adjacent upper vane means, so that at a particular end portion of the blade member the upper vane means is inclined at a net angle to the lower vane means when viewed along the axis of rotation.   
     
     
       13. An apparatus as claimed in claim 12 in which: (a) each lower vane means comprises at least one vane member inclined at an angle to the direction of rotation of the blade member so as to direct the material that is below the blade member inwardly toward the axis of rotation of the blade member.   
     
     
       14. An apparatus as claimed in claim 13 in which: (a) each upper vane means is a vane member inclined at an angle to the direction of rotation of the blade member so as to direct material that is above the blade member outwardly away from the axis of rotation of the blade member.   
     
     
       15. An apparatus as claimed in claim 12 in which: (a) the lower vane angle is between about 100 and 120 degrees, as measured on an inwardly disposed leading side of the blade axis defined with respect to direction of rotation of the blade member,   (b) the first and second lower vane means are disposed parallel to each other when viewed along the axis of rotation of the blade member.   
     
     
       16. An apparatus as claimed in claim 12 in which: (a) the upper vane angle is between about 70 degrees and 50 degrees, as measured on an inwardly disposed leading side of the blade axis defined with respect to direction of rotation of the blade member;   (b) the first and second upper vane means are disposed parallel to each other when viewed along the axis of rotation of the blade member.   
     
     
       17. A method of clearing snow or other particulate or fragmented material, the method comprising the steps of: (a) moving generally vertically disposed lower vane means in a circular lower arc about a generally vertical axis of rotation to cut the snow or material, the lower vane means being inclined obliquely to respective tangents to the lower arc to move the cut material inwardly towards the axis;   (b) moving generally vertically disposed upper vane means in a circular upper arc disposed above the lower arc about the said axis, the upper vane means being inclined obliquely to respective tangents to the upper arc to move the material outwardly away from the axis.   
     
     
       18. A method as claimed in claim 17 further characterized by: (a) simultaneously with moving the upper and lower vane means through respective arcs, moving the axis of rotation in a feed direction generally normally to the axis of rotation, so as to feed the snow or material into the lower arc.   
     
     
       19. A method as claimed in claim 18 further including: (a) tilting the axis of rotation rearwardly in a direction opposite to the feed direction of the axis, so as to incline the arc out of a horizontal plane to facilitate feeding material into the lower arc.   
     
     
       20. A method as claimed in claim 17 in which: (a) the upper and lower arcs have generally similar radii, and   (b) the lower and upper vane means rotate together.